Congenital abnormalities of the kidney and the urinary tract (CAKUT) are the most common cause of pediatric kidney failure. These disorders are highly heterogenous, and their etiology is poorly understood. Many forms of CAKUT are familial, but because they may be asymptomatic, they require large-scale clinical screening in order to be identified. CAKUT contributes to 23% of birth defects,1,2 accounting for 40-50% of pediatric and 7% of adult end-stage renal disease (ESRD) worldwide.3,4 These disorders are genetically heterogeneous and encompass a wide range of anatomic defects, such as renal agenesis (RA), renal hypoplasia (RHD)/dysplasia, uretero-pelvic junction obstruction (UPJO), or vesicoureteral reflux (VUR).5 Mutations in genes that produce syndromic disorders, such as HNF1B and PAX2, are detected in only 5-10% of cases.6,7 Familial forms of nonsyndromic disease have been reported, further supporting genetic determination;8,9 but, owing to locus heterogeneity and small pedigree size, the genetic etiology for most familial or sporadic cases remains unknown.